Internal-brake-adjusting mechanism



Oct. 14, 1930. L. A. LJDHOLM 1,778,112

INTERNAL BRAKE ADJUSTING MECHANISM Filed D90. 28, 1928 a a j .lewazw/AZrbZo/m Patented Oct. 14, 1930 NITE STATES PATENT OFFICE LEONE)ALFRED LIDHOLM, 0F MINNEAPOLIS, MINNESOTA, ASSIGNOB OF ONE-HALF TOALFRED '1. LIDHOLM, 0F MINNEAPOLIS, MINNESOTA IN TEBNAL-BRAKE-ADJ'USTING MECHANISM Application filed December 28, 1928. Serial No. 828,898.

My invention relates to internal brake adjusting mechanism intended forgeneral use, but especially well adapted for use in connection with thebrakes of a motor propelled vehicle.

The invention, as illustrated, is embodied in an internal brakemechanism of that type employing a pair of horizontally opposedcircumferentially extended brake shoes arranged to be expandedinternally ontoa brake drum, and having adjusting devices at their upperand lower ends for adjusting said shoes in respect to the drum. Theadjusting devices for the lower end portions of these brakeshoes are inthe form of eccentric anchor pins on which said shoes are pivotallymounted. Great difiiculty is experienced in adj usti g this type ofbrake shoes for the reason thal the brake adjusting mechanism is encasedin the drum where it can not be seen and operable from the outsidethereof. To

adjust the brake shoes it is customary to first adjust the. upper endportions thereof and thereafter adjust the lower end portions of thesaid shoes by means of the eccentric anchor pins. In certain positionsof the eccentrio anchor pins they impart circumferential movements tothe brake shoes in respect to the drum as well as radial movements andhence throw the upper end portions of the brake shoes out of adjustmentsin respect to the drum 12 and as these pins cannot be seen, it is oftendificult to properly position the same.

in order to facilitate the adjustment of the brake shoes it is quite thegeneral ractice to remove the wheels of the vehicle, w ich, of course,removes the bralre-v drums that are attached thereto, to aiford accessto the brake mechanism. With the brake drum removed it is necessary toemploy a false drum in the form of a ring which temporarily takes theplace of said drum. This ring is removably mounted on the Wheel spindleconcentric thereto and having the same internal diameter as that of thebrake drum in order that the brake shoes may be adjusted thereto. Thebrake. shoes when thusadjusted are properly positioned for action on thebrake drum when of the brake shoes at their upper end portions.

To the above end, generally stated, the invention consists of the noveldevices and combinations of, devices hereinafter described and definedin the claims.

In the accompanying drawings, which illustrate the invention, likecharacters indicate like parts throughout the several views.

Referring to the drawings:

Fig. l is a fragmentary view showing the invention embodied in aninternal brake mechanism for an automobile wheel;

Fig. 2 is a view partly in elevation and partly in vertical sectiontaken on the line 2-2 of Fi 1;

Fig. 3 is a fragmentary view partly in plan and partly in horizontalsection taken on lthe line 3-3 of Fig. 2, on an enlarged sca c;

Fig. 4 is a fragmentary detail view with ipme parts sectioned on theline 4- .3; of

1% lg. 5 is a View corres ending to Fig. 4. with the exception that thesectioned parts thereof are shown in full;

Fig. 6 is a fragmentary detail view with some garts sectioned on theline 66 of Fig. 3; an

Fig. 7 is a perspective view of one of the blocks removed from thebearing plate.

The numeral 8 indicates the front axle of an automobile to which thewheel spindle assembly 9 is connected b a king pin 10. A wheel 11 ismounted on t e spindle assembly 9 and a brake drum 12 is bolted to saidwheel at its inner face and concentric with the axis thereof. Thecustomary dust shield 13 for the inner open face of the drum 12 isjgigidly secured to the wheel spindle assemllflounted within the drum 9for cooperation therewith is a pair of horizontally oposedcircumferentially extended segmental iirake shoes 14 to the peripheriesof which brake linings 15 are applied.

In the present mounting of the brake shoes said pins the brake shoes maybe adjusted in respect to the drum 12. The purpose of my invention is tosubstitute other adjusting means for these eccentric anchor pins as willpresently be described.

The upper ends of the brake shoes ,14 are adjusted in respect to thedrum 12 by means of cams 16 pivoted to the dust shield 13 forcooperation with cam pins 17 rigidly secured to the brake shoes 14 andprojects laterally therefrom, These cams 16 are individually operablefrom the outside of the dust shield 13 and by turning the same the upperend portions of the brake shoes 14 may be ad- 'usted toward or from thedrum 12. The hrake shoes 14 are connected and normally andyieldinglysheld retracted by a coiled 18 the ends of which are attachedto sprin I said s oes and ided by ms 18 near the r free ends. A ydraulicraking system is used for expanding the brake shoes 14 against thedrurn12 and of the parts thereof there is shown the brake cylinder 19containing a braking fluid which acts on a pair of pistons in saidcylinder. Said pistons are provided with stems 20 that are reverselyextended through the heads of the cyhnder 19 and attached to the freeends of thebrake shoes 14. The arts thus far described are of standardan well known construction.

Referring now in detail to the invention, the numeral 21 indicates apair of headed anchor studs that extend through the bores in the lowerends of the brake shoes 14 and support said shoes for pivotal movementsthereon. These anchor studs 21 have reduced intermediate bod portions 22that extend through holes 23 in a pair of blocks 24. The stud bodyportions 22 are square in cross section and snugly fit in the holes 23that are correspondingly formed to hold the studs 21 from turning in theblocks 24. Shoulders 25 on the studs 21 engage the blocks 24 and limitthe movements of said studs into said blocks. The brake shoes 14 areheld against axial movements on the studs 21 by the' means idly securedto the outer face of the dust shield 13 directly under the spindleassembly 9. This way '26 extends, as shown,'tan

gential to an are having its center at the axis of the drum 12. To holdthe blocks 24 for straight line sliding movements in the way 26 eithertoward or from each other, they are rabbeted at 24 and fitted onto thelongitudinal edge portions of the bearing plate 27 at said way.

On the outer end portions of the studs 21 are axially extendedscrew-threaded stems 28 to which are applied washer-like clamping plates29 and nuts 30. These clamping plates 29 span the-way 26 and rest on thebearing plate 27 on opposite sides of said way. By reference to Figs. 3and 6, it will be noted that the blocks 24 do not extend completelythrough the way 26 so as to not interfere with the clamping action ofthe plates 29. By tightening the nuts 30on the stems 28 opposingmovements are imparted to the blocks 24 and clamping plates 29 tofrictionally clamp said blocks and plates on opposite sides of thebearing plates 27 for adjustably and rigidly holding said blocks.

An expanding device in the form of a wedge 31 is provided for separatingthe blocks 24 and hence the pivoted or lower ends of the brake shoes 14to adjust the same onto the drum 12. This wedge 31' is mounted in a pairof opposed cam seats 32 formed in the blocks 24 and has rigidly securedthereto an axially extended screw-threaded stem 33 which projectsthrough the way 26 and has applied thereto a washer-like clamping plate34 and a nut 35. The clamping plate 34 extends between the clampingplates 29, spans the way 26 and rests on the bearing plate 27 atopposite sides of said way. A coiled spring 36 extends between thepivoted ends of the brake shoes 14, is attached at its ends theretovandunder strain to pull the respective ends of the brake shoes14 towardeach other to release the same from'the brake drum 12 and hold theblocks 24 with their cam seats 32 in contact with the expanding wedge31.

To adjust the brake shoes 14 to the drum 12 the cam-acting members 16are first operated from the outside of the drum 12 one at a time toposition the upper or free end portions of the brake shoes 14 so thatthey just touch said drum. After the upper ends of the brake shoes 14are properly adjusted in respect to the drum 12, one of the nuts 30 isloosened to release the respective blocks 24 and hence the pivoted lowerend of the connected brake shoe 14. With this nut 30 released the nut isoperated to draw the expanding wed e 31 downward on the cam seats 32 andthereby move the released block 24 in the way 26suificiently to causethe lower end portion of the released brake shoe 14 to just touch thedrum 12. This last adjustt rtar 11a ment of the released brake, shoe 14does not in any way efiect the adjustment of the upper end of said shoewhich was by the respective cam 16..

During the expanding action of the wedge 31 on the released block 24,the other block 2% which is rigidly secured to the bearing late 2'? actsas a base or" resistance therefor, fter the lower end of the releasedbrake shoe 1t isv properly adjusted to the drum 12, its nuts 30 areagain tightened to rigidly clamp said block onto the bearing plate 27.lhe lower end of the other brake shoe is is next adjusted in similarmanner After the lower ends of the brake shoes'l have been properlyadjusted and the blocks 24: rigidly clamped on to the bearing plate 27by means of the clamp out their entire braking surfaces.

ing plates 29 and nuts 30 to hold the same where set the cams 16 areagain operated to' slightly release the upper ends of the brake shoes14; and permit the spring l8to draw said shoes awafrom thedrum 1.2.

This last a justrnent is to position the-- brake shoes, when released,in such relation to the drum 12 that when set against the drum 12 theywill engage the same through:

it is highly important to note that the straight line sliding movementsof the pivot studs 21 during the adjustments'ot the lower ends of thebrake shoes it is such as to not interfere with or change theadjustments of the upper end portions of said shoes in which they areheld by the cam 16. The springs-18 and 36 hold the brake shoes, whenreleased,

so that they are quiet.

\ What I claim is:

1. The combination with a brake drum and a support therein of. a pair ofopposed brake shoes arranged ior internal action on the drum, anchormembers attachin the brake shoes to the. support, andimeans $62expanding the brakeshoes onto the drum, said anchor members beingmounted on the sup ort for substantially straight line sliding ad ustments tangential to an are having its center at the axis of the drum,and. an expanding device for moving the anchor members to adjust thebrake shoes toward the drum said anchor members having individual meansfor adjustably but rigidly securing said members to the support.

2. The combination with a brake drum and a supporttherein, of a air ofopposed brake shoes arranged for in ernal action on the drum, means forex ending the brake shoes onto the drum, a pair of blocks mounted in away in the support for independent previously made for moving the blocksto adjust the brake shoes in respect to the drum, I 4a. The structuredefined in claim 2 in fur ther combination with an ex ending device formovingthe blocks to a just the brake shoes in respect to the drum, saidexpanding device having means for operating the same from the oppositeside of the support from the brake shoes. 5., ihe structure defined inclairn'fi in fun ther combination with an expanding device tierinovingthe blocks to adjust the brake yieldingly holding the blocks with theircam seats contacting with the expanding wedge, said. expanding wedgebeing operable from the oppositeslde oi the support from the brake shoesand having means for adjust cg;

ably and rigidly securing the same to the support,

8. The combination with a brake drum. l

and a support therein of a pair ofopposed brake shoes arranged forinternal action on the drum, means for expanding the brake shoes ontothe drum, pair of blocks mounted in a way in the sup ortfor inde endentadjustment toward or rom each 'ot or, an chor studs mounted in theblocks and pivotally connecting the brake shoes thereto, saidanchorstuds being held from turning in' the blocks and having washersand nuts applied thereto for adjustabiy and rigidly securing the blocksto the support, an expanding wedge mounted in 'opjposed cam seats in theblocks and operable 'rom the opposite side of the su port from the'hrakeshoes to sepa=.

ice

ltlti rate the locks and adjust said shoes toward the drum, and a springyieldingly holding the blocks with their cam seats in contact with theer'panding'wed e. v

In'testimony whereof afix m si aturcl LEONARD ALFRED Lll lig slidingmovement toward or from each other,

and anchor studs pivotally attaching the brake shoes to the b ocks, saidanchor studs having clam ing devices for adjusta'oiy and rigid lf 3. hestructure defined in claim 2' 1n fursecuring the blocks to the, support.

ther'combination with an expanding device

